Preparation of collodion for the manufacture of artificial silk.



UNITED STATES PATENT 'OEEICE.

JULEs DOUGE, or-rnms, FRANCE.

PREPARATION .OF COLLODION FOR THE MANUFACTURE OF ARTIFICIAL SILK.

SPECIFICATION forming part of Letters Patent No. 699,155, dated May 6,1902. Application filed March 6, 1902. Serial No. 97,000. (Nospecimens.)

To all whom it may concern.-

Be it 'known that I, JULEs DOUGE, a citizen of the Republic of France,residing in Paris, France, have invented certain new and usefulImprovements in the Preparation of Collodion for the Manufacture ofArtificial Silk, of which the following is a specification.

In the present state of the manufacture of artificial silk fromsolutions of nitrocellulose in a mixture of alcohol and other thecollodion employed is preparedfrom pyroxylin in two diiferentconditions. In the one case anhydrous pyroxylin is employed, this beingobtained in this state either by washing with alcohol or ether or moregenerally by drying it in a stove at a temperature more or less high. Isis then dissolved in a mixture of alcohol and ether, so as to obtaincollodion suitable for being formed into threads of artificial silk.Pyroxylin thus obtained has the very serious defect that it can beeasily exploded, and therefore involves risks during ,manipulation, themore so as by drying the pyroxylin to the anhydrous condition it becomesacid by the liberation by the heat of part of the nitric acid in itscomposition. This acidificationof the pyroxylin is irregular, owingto'the variations of the temperature to which it is subjected and of thetime of its exposure, depending on the hydrometric condition of theatmosphere. This irregularity in the acidity of the pyroxylin causesirregularities in the character of the collodion, which are verydetrimental in the manufacture of silk. The second method of producingthe collodion consists in the use of a pyroxylin hydrate which after thewashing after nitration contains twenty-five to thirty per cent. ofwater. In this hydrate condition it is used for producing collodion bythe alc.o-

-hol and ether solvent. The objection to this second method'is that thepyroxylin containing twenty-five to thirty per cent. of water becomespartially decomposed, especially under the influence of sunlight, sothat it hasto be at once employed in order to produce a collodion alwaysof the same character capable of being easily formed into threads ofgood quality. This defect is very serious in practice, for in certaincases, especially when there is unforseen retardation in the output ofthe collodion thread, it is necessary to stop the process for a time andto keep back the pyroxylin already manufactured.

In order to avoid the difficulties attending the two methods abovedescribed of producing collodion, I have made investigations which haveled me to a new process, for which I now apply for a patent.

I operate in the following manner: After the washing of the pyroxylin Isubject it to centrifugal action or pressure until all the water thatcan be extracted in this way is eliminated and Without regard to theamount that may still be held by it. The pyroxylin is then exposed onscreens to the open air in the shade or in a chamber having a current ofair passing through it.- This exposure of the pyroxylin to air is to bemaintained until the average hygroscopic condition is obtained-say sixto ten per cent. In this state the pyroxylin can be kept for anindefinite period in a cool place without danger of heating,acidification, or oxidation. In moist and cold weather in order to avoidprolonging excessively the time of exposing the pyroxylin to the air,which might be practically objectionable on account of the large spacewhich the screens'would occupy, there may be sent into thedrying-chamber air previously heated in a separate chamber provided withpipes for circulation of hot water or of low-pressure steam or othermeans of heating the air not above 25 to 30 centigrade. In this way thedecomposition (even partial) of the pyroxylin is certainly providedagainst. I prefer, however, the heating of the air by hot water or 10w-pressure steam on account of the regularity and certainty which thismethod insures. The transformation of the pyroxylin into collodion isobtained by subjecting it to a solvent compounded in proportions suitedto the quality or source of the cellulose employed for producing thepyroxylin. This solvent consists of a mixture of alcohol and ether, withthe addition of an aqueous alkaline solution-such as potash,

soda, ammonia, or their carbonates, lithia, lime, baryta, sodium borate,potassium or sodium silicate, or the likewhich has the effect ofneutralizing, as it is produced, the acid, which is always formed whenthe solvent of the pyroxylin, whatever it may be, evaporates, such asmixture of alcohol and ether, acetone, or acetic ether. This productionof acid seriously interferes with the subsequent operations andinjuriously affects the strength and durability of the artificial silk.

Having thus described the nature of this invention and the best means Iknow of car rying the same into practical effect, I claim- 1. Theprocess above described for manufacturing artificial silk by means ofcollodion obtained by the solution of pyroxylin air dried atlowtemperatures until itcontaius six to ten per cent. of water, in amixture compounded according to the quality of the cellulose employed ofether, alcohol and an aqueous alkaline solution (potash, soda, ammonia,or their carbonates, lithia, lime, baryta, sodium borate, potassium orsodium silicate or the like).

2. The process of preparing collodion for the manufacture of artificialsilk which consists in Washing pyroxylin, subjecting it to centrifugalaction to eliminate water therefrom, exposing the same to a dryingatmosphere until it is brought to a hygroscopic condition of about sixto ten per cent.,and subjecting it to the action of a mixture ofalcohol,ether and an aqueous alkaline solution.

3. The process of preparing collodion for the manufacture of artificialsilk which consists in washing pyroxylin,snbjecting it to centrifugalaction to eliminate water therefrom, exposing the same to a dryingatmosphere until it is brought to a hygroscopic condition of about sixto ten per cent, and subjecting it to the action of a solvent.

4. The process of preparing collodion for the manufacture of artificialsilk which consists in subjecting pyroxylin to the action of a mixtureof alcohol, ether, and an alkaline solution.

5. The process of preparing collodion for the manufacture of artificialsilk which consists in bringing pyroxylin to a hygroscopic conditionofabout six to ten per cent. and subjecting it to the action of amixture of alcohol, ether and an alkaline solution.

In Witness whereof I have hereunto signed my name in the presence of twosubscribing Witnesses.

JULES DOUGE.

\Vitnesses:

JULEs ARMENGAUD, Jeune, MAREL ARMENGAUD, Aime.

